The present invention relates generally to vehicle supplemental inflatable restraint systems and, more particularly, to an inflator seal retainer and inflator seal members for use in air bag modules and a method of retaining the inflator therein.
Driver side or passenger side supplemental inflatable restraint (SIR) systems typically include an air bag stored in a housing module within the interior of the vehicle in close proximity to either the driver or one or more passengers. SIR systems are designed to actuate upon sudden deceleration so as to rapidly deploy an air bag to restrain the movement of the driver or passengers. During deployment, gas is emitted rapidly from an inflator into the air bag to expand it to a fully inflated state.
Air bag passive restraint systems include an inflator, which produces gas to inflate the air bag cushion. Known inflators for air bag modules are generally of three types. One type is the pure gas inflator wherein a pressure vessel contains stored pressurized gas. The pressure vessel communicates with the cushion through various types of rupturable outlets or diaphragms. Another type is the gas generator wherein a propellant is ignited and the resultant gas flow through an outlet to the cushion. A third type is the hybrid or augmented type. This type includes a pressure vessel containing stored pressurized gas and a gas generator. When the generator is ignited, the resultant gas flows with the stored gas to the cushion through the pressure vessel outlet.
It is also known to inflate the cushion at a relatively low rate under low level deployment conditions, such as a sudden low level deceleration, and at a relatively high rate under high level deployment conditions, such as a sudden high level deceleration. This can be accomplished in a pure gas type inflator by providing the pressure vessel with an outlet of variable flow area. In addition, devices are known which provide primary inflation (reduced inflation) and full level inflation using a single gas vessel with two separate gas heaters. Primary inflation is accomplished by actuating the gas vessel and heating the gas at a specified reduced level. Full level inflation is accomplished by actuating a second separate heater located at the bottom of the gas vessel to heat the gas at a greater level. This second heater is deployed at the same time or a delayed time as the primary heater to provide full level inflation. It is also known in the art to use a system having two discrete inflators to accomplish dual level inflation. In these types of systems, two discrete inflators are deployed at the same time or at a delayed time depending upon the severity of the sudden deceleration.
The inflator, along with the air bag cushion, is typically disposed within a module housing using molded seals and/or integral retainers to securely retain the inflator therein. However, the use of integral seal and the like adds complexity to both the manufacturing and assembly process and also increases costs and mass. It is desirable to provide an air bag module which utilizes a simple device for providing high quality seal retention of the inflator within the module housing.
This invention offers advantages and alternatives over the prior art by providing a device for retaining an inflator within an air bag module housing in a sealing manner. In a first embodiment, the device comprises an inflator seal member and an inflator seal retainer. The inflator seal member is disposed about an outer surface of the inflator by disposing the inflator through an opening formed in the inflator seal member. More specifically, the inflator seal member generally comprises a ring-like member having a generally annular inner surface which contacts the outer surface of the inflator. The inner surface preferably includes a plurality of ribs formed thereon to provide a frictional surface for gripping the inflator. The inflator seal member further has a perimetric edge which is received within a retaining groove formed in the module housing for locating and partially retaining the inflator within an internal cavity formed in the module housing.
The inflator seal retainer is designed to provide high quality seal retention between the inflator and the module housing. In a broad sense, the inflator seal retainer comprises a symmetric star shaped member having spring-like properties. In the exemplary and preferred embodiment, the inflator seal retainer is formed of a continuous piece of metal having a cross-section shape of a star. The inflator seal retainer has a first end defining an outwardly bent first prong and a second end defining an outwardly bent second prong. The inflator seal retainer is formed so that it includes a plurality of peaks radially disposed about a central opening defined by the inflator seal retainer. Because the inflator seal retainer has spring-like properties, the first and second prongs may be flexed outwardly to open the inflator seal retainer and permit the inflator to be initially disposed therein or readjusted relative to the inflator seal retainer. Once the first and second prongs are released, they return to their original position by flexing inwardly to thereby make contact with the outer surface of the inflator at distinct contact points. These contact points comprise points where a retention force is applied by the inflator seal retainer to the inflator.
The plurality of peaks of the inflator seal retainer serves to securely attach the inflator seal retainer to the module housing. More specifically, the plurality of peaks are received within a plurality of retaining slots formed in an arcuate wall of the module housing. This results in the inflator seal retainer being locked into place relative to the module housing. The plurality of peaks are elongated to provide enough interference with the plurality of slots so that it is difficult for the inflator seal retainer to come loose from the module housing after the inflator seal retainer is locked into place. Advantageously, the inflator seal retainer comprises a simple device which further positions and retains the inflator within the module housing. The spring-like properties of the inflator seal retainer permit the inflator seal retainer to adapt to variances in inflator diameter and facilitate ease of assembly and disassembly. The simple design provides a means for dismantling the air bag module for material recovery/recycling and provides other benefits mentioned hereinafter.
In a second embodiment, an inflator seal member of a second embodiment is provided and disposed about the outer surface of the inflator by disposing the inflator through a central opening formed in the inflator seal member. More specifically, the inflator seal member generally comprises a ring-like member having an annular inner surface which contacts the outer surface of the inflator. The inner surface preferably includes a plurality of ribs formed thereon to provide a frictional surface for gripping and retaining the inflator. The inflator seal member has a perimetric edge which is received within the retaining groove formed in the module housing for locating and partially retaining the inflator seal member and the inflator within an internal cavity formed in the module housing. An annular outer surface of the inflator seal member includes a plurality of retaining tabs extending therefrom. The plurality of retaining tabs serves to lock the inflator seal member in place in the module housing by insertion of the plurality of retaining tabs into the plurality of retaining slots. Because the inflator is securely disposed within the opening formed in the inflator seal member, the inflator seal member provides a device for sealing the air bag module housing and securing the inflator therein.
In a third embodiment of the present invention, an inflator mounting bracket is provided. The inflator mounting bracket includes a base surface at a closed first end and is open-ended at a second opposing end. The inflator mounting bracket includes a plurality of first arms extending from the base surface and a plurality of second arms extending also from the base surface towards the second end, wherein the first arms have a length less than a length of the second arms. In the exemplary embodiment, there are three first arms, wherein two first arms are disposed about 180xc2x0 to each other and a third first arm is disposed intermediate the other two and generally 90xc2x0 from the other two. The second arms are generally disposed so the first arms are disposed between a pair of next adjacent second arms except that one pair of next adjacent second arms does not include a first arm disposed therebetween. Each of the second arms includes a flange at an end opposite the base surface, wherein the flange is designed to be disposed within the retaining groove of the module housing.
The inflator mounting bracket also includes an opening formed in the base surface, wherein the opening receives a stud which preferably extends from one end of the inflator. The opening thus serves to properly position and secure one end of the inflator within the module housing, while the other end of inflator and inflator mounting bracket is positioned and secured within the module housing by inserting the flanges into the retaining slot. Because the plurality of second arms are sufficiently resilient, the second arms may be flexed outwardly apart from one another to permit the inflator to be inserted therebetween and the second arms may also be flexed inwardly to permit the flanges thereof to be aligned with the retaining slot. Once the second arms are released, the second arms flex outwardly causing the flanges to engage the retaining slot. This results in the inflator mounting bracket and the inflator disposed therein to be properly positioned and retained within the module housing.
The devices of the present invention each provide uniform and continuous retention force exerted against the inflator and the module housing which acts to securely position and retain and seal the inflator within the module housing. The simple designs of the devices permit the air bag module to be serviceable and also provides a means for dismantling the air bag module for material recovery/recycling.
The above-described and other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims.